Search

The grafting technique has successfully mitigated crop losses from diseases and stress in vegetable production; however, vegetable grafting in Tanzania is very limited. Field and greenhouse experiments conducted in Tanzania's mainland and islands compared the response of tomato determinate cv. 'Tanya' to production challenges when ungrafted and grafted onto five tomato rootstocks ('Hawaii 7796', 'Tengeru 1997', 'Tengeru 2010', 'R3034', and 'Shelter'), one eggplant variety ('EG 203'), and one wild Solanum species (Solanum elaeagnifolium). The visual symptoms of bacterial wilt varied significantly with location and season, ranging from 8 to 100%, attributed to varying bacterial wilt pressures and strains of Ralstonia solanacearum isolated (Phylotype I sequevars 17, 18, and 31). 'EG203' and 'Hawaii 7796' emerged as the most effective rootstocks, reducing wilting by 49.8 and 51.0% and improving yield by 57.2% and 27.7% on average across experiments conducted in three locations (Moshi, Pemba, and Unguja) over two seasons. Combining reduced water supply with grafting resulted in an average reduction in wilting of 76%, while also boosting yields by an average of 3.6 times in experiments conducted in Arusha over two seasons. Grafting onto 'Hawaii 7796' and 'Shelter' significantly improved 'Tanya' yields by 38.3% and 41.6% on average over two seasons, only under standard nutrient application rates. While certain rootstocks improved crop performance, yields across various sites and seasons were significantly hampered by pest pressure. These findings support grafting's potential to mitigate damage from common stresses, emphasizing the need for further research to identify suitable rootstocks for optimizing returns on investments in grafted plants in Tanzania. [ABSTRACT FROM AUTHOR]

Vegetable grafting is developing worldwide to cope with biotic and abiotic stresses. This technique faces strong regional disparities and its potential to improve crop performances is currently underexploited in sub-Saharan Africa. This review explores the potential of grafting to increase and secure vegetable production in challenging production conditions in sub-Saharan Africa and to identify the obstacles to its adoption. The major conclusions that can be drawn from the review are (1) the capacity of vegetable grafting to overcome several agronomic challenges commonly encountered in sub-Saharan Africa particularly for soilborne diseases; (2) grafting does not systematically lead to higher yields since the performance of grafted plants is closely linked with the combination of scion–rootstock chosen; (3) resistant rootstocks to the local soilborne pathogens could be identified through short-term laboratory and field experiments whereas the improvement of the tolerance to abiotic stresses would require deeper knowledge on underlying mechanisms; (4) the significant increase in the cost of using grafted plants are warranted in systems where there are no other technical alternatives to manage biotic and abiotic stresses, where profitability per plant is high, or where the use of grafted plants makes it possible to reach a profitable niche market such as off-season or organic products; and (5) vegetable grafting should therefore be promoted by providing evidence for its profitability in different production systems (open field and greenhouse cultivation) combined with supply-side interventions to build or strengthen the capacity of nursery operators to provide a continuous supply of good-quality grafted plants. [ABSTRACT FROM AUTHOR]